Method and device for welding conductor ends

Abstract

The invention relates to a welding method for welding conductor ends (24, 24.1, 24.2) of a component (26) for an electrical machine grouped in a conductor end group (64), wherein at least a first conductor end (24, 24.1) of the conductor end group (64) and a second conductor end (24, 24.2) of the conductor end group (64) are to be joined together in a joining area (66) of the conductor end group (64), where the first conductor end (24.1) and the second conductor end (24.2) are located next to each other. To improve the quality of the weld, it is proposed that the welding process includes the following steps: a) directing a welding jet (68) towards the joining area (66) of the conductor end group (64) to create a weld pool (70), and b) moving the welding jet (68) out of the joining area (66) into an edge area (72) of the conductor end group (64) and terminating the emission of the welding jet (64) there.

Description

[0001] The invention relates to a welding method for welding conductor ends of a component for an electric machine that are grouped together in a conductor end group. It further relates to a manufacturing method for producing a coil winding of a hairpin stator using such a welding method. The invention further relates to a welding device for welding conductor ends of a component for an electric machine that are grouped together in a conductor end group. The invention further relates to a manufacturing system for producing a hairpin stator that includes such a welding device. Finally, the invention relates to a computer program with instructions for carrying out the welding method.

[0002] Some embodiments of the invention relate to a method to be carried out in the course of series production of a component of an electrical machine for welding conductor ends which are arranged on the component in a conductor end arrangement.

[0003] Methods and devices according to embodiments of the invention are intended for use in particular in the manufacture of flat wire stators, especially hairpin stators. In hairpin stators, the coil winding is formed from a plurality of hairpin-like bent conductor sections (called hairpins) that have two legs with free conductor ends, connected to each other by a roof-like bent section. The hairpins are inserted into stator slots, and the coil winding is then formed, usually by welding the conductor ends together in pairs. Some embodiments of the invention relate to such welding of conductor ends, in which the positions of the conductor ends are also detected during the welding process.

[0004] Regarding the technological background and the state of the art, particular reference is made to the following literature references, which are integrated by reference and form part of this disclosure: [1] EP 3 750 231 B1 [2] EP 3 533 134 A1 [3] EP 3 797 918 B1 [4] EP 3 865 242 B1 [5] EP 4 104 963 B1 [6] Wikipedia: Electron beam material processing; downloaded on 26.04.2024 from https: / / de.wikipedia.org / wiki / Elektronenstrahl-Materialbearbeitung

[0005] From [1] a manufacturing plant for a hairpin stator and a manufacturing method for producing the coil winding of such a hairpin stator are known. In this process, conductor ends are welded together using a welding process. [2] discloses a welding template that can be used in the welding process. [3] to [5] disclose welding processes and welding devices with the features of the preamble of the independent claims.

[0006] The invention aims to improve the welding of conductor ends of a component for an electrical machine grouped in a conductor end group - in particular with regard to the reliability and / or quality of the welded joint.

[0007] To solve this problem, the invention provides a welding method according to claim 1. A manufacturing method for producing a coil winding of a hairpin stator using such a welding method, a welding device for carrying out the welding method, a manufacturing plant for a hairpin stator comprising such a device, and a computer program product with instructions for carrying out the welding method are the subject of the dependent claims.

[0008] Advantageous embodiments are the subject of the dependent claims.

[0009] According to a first aspect thereof, the invention provides a welding method for welding conductor ends of a component for an electrical machine grouped in a conductor end group, wherein at least a first conductor end of the conductor end group and a second conductor end of the conductor end group are to be joined together in a joining area of ​​the conductor end group where the first conductor end and the second conductor end lie next to each other, wherein the welding method comprises the steps: a) Directing a welding jet onto the joining area of ​​the conductor end group to create a molten pool, and b) moving the welding jet out of the joining area into an edge area of ​​the conductor end group and terminating the emission of the welding jet there.

[0010] In some embodiments, the welding process includes the step of positioning the ladder ends of the ladder end group to be welded by clamping them using a clamping template.

[0011] In some embodiments of the welding process, a laser beam is directed at the conductor end group as the welding beam.

[0012] In some embodiments, step a) comprises scanning the joining area with the welding jet, wherein the joining area is elliptical, polygonal, in particular rectangular, multi-zone or linear.

[0013] In some embodiments, step b) includes step: b1.1) moving the welding jet into a corner area of ​​the conductor end group.

[0014] In some embodiments, step b) includes step: b1.2) moving the welding jet into an edge region of the weld pool.

[0015] In some embodiments, step b) includes step: b1.3) moving the welding jet into an edge region of a conductor end of the conductor end group.

[0016] In some embodiments, step b) includes step: b1.4) moving the welding jet into an edge region of an end face of a conductor end of the conductor end group.

[0017] In some embodiments, step b) includes step: b1.5) Proceeding the welding jet to an edge of a conductor end.

[0018] In some embodiments, step b) includes step: b1.6) moving the welding jet so that it strikes a side surface of the conductor end group, in particular one conductor end thereof.

[0019] In some embodiments, step b) includes step: b1.7) moving the welding jet so that it hits a clamping template outside the conductor end group.

[0020] In some embodiments, step b) includes step: b1.8) moving the welding jet so that it hits a sacrificial plate provided for this purpose outside the conductor end group.

[0021] In some embodiments, step b) includes step: b2.1) Inserting an aperture into the welding jet.

[0022] In some embodiments, step b) includes step: b2.2) Switching off the welding jet.

[0023] Some embodiments of the method include repeating steps a) and b) to weld conductor ends of another conductor end group of the component.

[0024] In particular, in some embodiments the steps are repeated until all conductor ends of the component to be welded are welded.

[0025] In some embodiments, the welding process includes the step to be carried out before step a): 0) Determining the position and / or arrangement of the conductor ends of the conductor end group to be welded.

[0026] Some embodiments of the welding process further include the following step: 1) Determining the location where the emission of the welding jet ends, depending on the position and / or arrangement identified in step 0).

[0027] In some embodiments, step 0) includes step: 01) Performing optical position detection.

[0028] In some embodiments, step 0) includes step 2) performing camera-based position detection.

[0029] In some embodiments, step 0) includes step 3) taking an image of at least a partial area of ​​the conductor arrangement and performing image processing to determine the position of conductor end groups to be welded.

[0030] In some embodiments, step 0) includes step 4) performing a camera-based detection of the position of conductor end groups by means of edge detection based on contrast difference.

[0031] In some embodiments, step 0) includes step 5) capturing a camera image and searching for a trained pattern, in particular based on contrast difference.

[0032] In some embodiments, step 0) includes step 6) performing optical coherence tomography (OCT).

[0033] In some embodiments, step 0) includes step 7) detection by means of an electron beam.

[0034] According to a further aspect, the invention provides a manufacturing method for producing a coil winding of a hairpin stator, characterized by forming the coil winding from a plurality of hairpin-shaped conductor sections, wherein conductor ends of the conductor sections are joined by means of a welding process according to one of the preceding embodiments.

[0035] According to a further aspect, the invention provides a welding device for welding conductor ends of a component for an electrical machine that are grouped in a conductor end group, wherein at least a first conductor end of the conductor end group and a second conductor end of the conductor end group are to be joined together in a joining area of ​​the conductor end group, where the first conductor end and the second conductor end are located next to each other, wherein the welding device comprises: a welding device with which a welding jet can be directed onto the conductor end arrangement, and a control which is configured to direct the welding device to direct a welding jet onto the joining area of ​​the conductor end group in order to create a weld pool, and to move the welding jet out of the joining area into an edge region of the conductor end group and to terminate the emission of the welding jet there.

[0036] In some embodiments, the welding device has a holder for the component from which the conductor ends to be joined protrude in a conductor end arrangement.

[0037] In some embodiments, the welding device has a welding template for positioning the conductor ends.

[0038] In some embodiments, the welding device has a position detection device which is designed to detect the position and / or arrangement of the conductor ends of the conductor end group to be welded.

[0039] In some embodiments, the position detection device is designed to determine the position of predetermined conductor ends to be welded within the conductor end assembly. In some embodiments, the position detection device comprises a non-contact sensing device for detecting the position and a computer-implemented evaluation unit.

[0040] In some embodiments, the non-contact detection device is configured to perform step: 01) Performing optical position detection.

[0041] In some embodiments, the non-contact detection device is set up to perform step: 02) Performing camera-based position detection.

[0042] In some embodiments, the non-contact detection device is configured to perform step 3) capturing an image of at least a partial area of ​​the conductor arrangement and performing image processing to detect the position of conductor end groups to be welded.

[0043] In some embodiments, the non-contact detection device is configured to perform step 4) Performing a camera-based detection of the position of conductor end groups by means of edge detection based on contrast difference.

[0044] In some embodiments, the non-contact detection device is configured to perform step 5) capturing a camera image and searching for a trained pattern, in particular based on contrast difference.

[0045] In some embodiments, the non-contact detection device is configured to perform step: 06) Performing optical coherence tomography (OCT).

[0046] In some embodiments, the non-contact detection device is configured to perform step 7) detection by means of an electron beam.

[0047] The welding device is preferably configured to position the welding jet at the conductor ends to be welded, depending on the position determined by the position determination device; in some embodiments, the welding device has a determination device that is configured to determine the location where the emission of the welding jet terminates, in particular depending on the position and / or arrangement detected by the position detection device.

[0048] In some embodiments, the welding device is selected from the group comprising a laser device for directing a laser welding beam onto the conductor ends to be welded and an electron beam welding device for directing an electron beam onto the conductor ends to be welded.

[0049] In some embodiments, the control system is designed to cause the welding device to carry out the welding process according to one of the preceding configurations.

[0050] According to another aspect, the invention provides a manufacturing plant for producing a hairpin stator, comprising a welding device according to one of the preceding embodiments.

[0051] According to another aspect, the invention provides a computer program comprising instructions that cause a welding device according to one of the preceding embodiments to carry out the welding process according to one of the preceding configurations.

[0052] Some particular advantages of preferred embodiments of the invention, as well as some technical effects of the steps or features provided therein, are explained below.

[0053] Some preferred embodiments of the invention relate to reducing process porosity during laser beam welding of hairpin wire ends by selectively positioning the emission end. These embodiments are particularly suitable for the large-scale industrial production of electric motors for electromobility. Some embodiments are especially applicable to the welding of conductor wire connections, for example, for manufacturing coil windings of electric motors or for connecting electric motors, e.g., for connecting a connecting element by welding the connecting wires of the connecting element to the connecting wires of a component of the electric motor. A particularly advantageous application lies in the field of manufacturing hairpin stators, especially for traction motors of electric vehicles.

[0054] As described in [1], a large number of conductor end groups, especially conductor end pairs, are joined by welding to connect individual hairpin-shaped wire sections inserted into a laminated core – called hairpins – to form a coil winding of the stator. The welded joints are intended to ensure a reliable electrical and mechanical connection. In particular, when welding with a welding beam – e.g., laser welding or electron beam welding – pores can form in the weld bead, which affect the quality.

[0055] Some embodiments of the invention relate to the reduction of pore formation during laser beam welding of wire ends in the manufacture of flat wire stators (especially hairpin stators).

[0056] Current approaches to reducing pore formation include: The use of static / dynamic beam shaping (e.g., offered on the market by Trumpf under the name BrightLine Weld); use of a laser power ramp at the end of the welding process; use of a laser spot velocity ramp at the end of the welding process; defocusing during the entire welding process or only at the end of the process; defocusing only at the end of the process

[0057] The disadvantages of static / dynamic beam shaping are that it is not usable or available for all laser types or other welding beam sources, that it changes the entire welding process, that it incurs high costs for the system technology, and that pore reduction is only possible to a limited extent because the end of the process cannot be reproducibly controlled.

[0058] A disadvantage of the laser power ramp is that reduced power increases the cycle time and pore reduction is only possible to a limited extent, as the end of the process cannot be reproducibly controlled.

[0059] A disadvantage of laser spot velocity end ramping is that pore reduction is only possible to a limited extent, as the end of the process cannot be reproducibly controlled.

[0060] Furthermore, a disadvantage of defocusing is that pore reduction is only possible to a limited extent, as the end of the process cannot be reproducibly controlled.

[0061] Preferred embodiments of the invention, on the other hand, offer a plant- and system-independent solution for reliably and reproducibly avoiding pore formation at the end of the process with minimal or no additional system technology.

[0062] Embodiments of the invention enable a reliable and / or reproducible reduction of pore formation and the resulting loss of quality in welded joints at conductor ends of electrical machines, while saving on system technology.

[0063] Challenges that had to be overcome in finding advantageous embodiments of the invention included, for example: The possibility of transferability to all conceivable welding geometries; the finding of a plant / system technology-independent solution; damage to any clamping tool that may be intended should be excluded / minimized; in some designs, high demands arose on the positioning of a laser beam on the wire ends to be welded; in some designs, the ideal position of the emission end between within the weld pool and damage to a clamping device had to be determined.

[0064] Some embodiments of the invention provide for the targeted positioning of the emission end during laser beam welding of flat wire conductors, thereby preventing porosity from forming at the process end. The solution can be used for all laser wavelengths, materials to be welded, laser types / classes, and all connections (wire to wire, wire to terminal element). Some embodiments provide for precise clamping of the components to be welded—in particular by means of the device described in [2]—and exact positioning of the welding geometry.

[0065] In some embodiments, the emission end is positioned so that a vapor capillary (keyhole) can be defined and terminated / opened outside the melt bath.

[0066] In some embodiments, the welding beam, for example designed as a laser beam, is moved to the edge / outside the wire ends without interrupting the welding process.

[0067] In some embodiments, the exit point is ideally positioned such that, due to a non-centric arrangement of the laser beam optics and the deflection angle of the laser beam, the latter strikes the wire end below the melt pool on the outside of the wire and is thus not directed towards a clamping device such as a clamping template. For this purpose, the emission end is located, in particular, on the side of the wire facing the optics.

[0068] In some embodiments, it is also possible to position the emission end minimally within the weld pool, close to its edge / the wire's edge. Due to the flat shape of the weld bead near the wire's outer edge, any pores that may form at the emission end can outgas. With this variant, damage to the clamping devices is ensured even with insufficient positioning accuracy.

[0069] In particular, some embodiments offer at least one, several or all of the following advantages: Complete reduction of process pores compared to conventional methods. Easy transferability to various projects / systems / plants / components. Usable for all laser types / wavelengths or beam sources. Suitable for different connections (wire to wire, wire to interconnect). No increase in cycle time due to laser power / laser spot velocity ramps / defocusing designed to reduce pore formation. Process strategy independent of the material to be welded. No additional / targeted system technology required.

[0070] Some embodiments of the invention are explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a schematic representation of a first embodiment of a device for welding conductor ends; Fig. 2 a schematic representation of a second embodiment of a device for welding conductor ends; Fig. 3a a top view of a pair of conductor ends as an example of a group of conductor ends to be welded by means of a welding process with an elliptical welding geometry; Fig. 3b the top view as in Fig. 3a in a conventional welding process with elliptical welding geometry; Fig. 3c the top view as in Fig. 3a in a welding process with the elliptical welding geometry according to a first embodiment of the invention; Fig. 3d the top view as in Fig. 3a in a welding process with the elliptical welding geometry according to a second embodiment of the invention; Fig. 3e the top view as in Fig. 3a in a welding process with the elliptical welding geometry according to a third embodiment of the invention; Fig. 4a a top view of a pair of ladder ends as an example of a group of ladder ends to be welded together by means of a welding process with a rectangular welding geometry; Fig. 4b the top view as in Fig. 4a in a conventional welding process with rectangular weld geometry; Fig. 4c the top view as in Fig. 4a in a welding process with the rectangular welding geometry according to a fourth embodiment of the invention; Fig. 4d the top view as in Fig. 4a in a welding process with the rectangular welding geometry according to a fifth embodiment of the invention; Fig. 4e the top view as in Fig. 4a in a welding process with the rectangular welding geometry according to a sixth embodiment of the invention; Fig. 5a a top view of a pair of ladder ends as an example of a group of ladder ends to be welded together by means of a welding process with a split welding geometry; Fig. 5b the top view as in Fig. 5a in a conventional welding process with the split weld geometry; Fig. 5c the top view as in Fig. 5a in a welding process with the split welding geometry according to a seventh embodiment of the invention; Fig. 5d the top view as in Fig. 5a in a welding process with the split welding geometry according to an eighth embodiment of the invention; Fig. 5e the top view as in Fig. 5a in a welding process with the split welding geometry according to a ninth embodiment of the invention; Fig. 6a a top view of a pair of ladder ends as an example of a group of ladder ends to be welded by means of a welding process with a split weld - line as welding geometry; Fig. 6b the top view as in Fig. 6a in a conventional welding process using gap welding; Fig. 6c the top view as in Fig. 6a in a welding process using gap welding according to a tenth embodiment of the invention; Fig. 6d the top view as in Fig. 6a in a welding process using gap welding according to an eleventh embodiment of the invention; Fig. 6e the top view as in Fig. 6a in a welding process using gap welding according to a twelfth embodiment of the invention; Fig. 7 a side view of the conductor end group of one of the Fig. 3a-3c, 4a-4c , 5a-5c und 6a-6c at one end of the welding process according to a first variant of the welding process of embodiments of the invention; Fig. 8 a side view of the conductor end group of one of the Fig. 3a-3c, 4a-4c , 5a-5c und 6a-6c at one end of the welding process according to a second variant of the welding process of embodiments of the invention; Fig. 9 a side view of the conductor end group of one of the Fig. 3a-3c, 4a-4c , 5a-5c und 6a-6c at one end of the welding process according to a third variant of the welding process of embodiments of the invention; Fig. 10 a side view of the conductor end group of one of the Fig. 3a-3c, 4a-4c , 5a-5c und 6a-6c at one end of the welding process according to a fourth variant of the welding process of embodiments of the invention; and Fig. 11 a side view of the conductor end group of one of the Fig. 3a-3c, 4a-4c , 5a-5c und 6a-6c at the end of the welding process according to a first variant of the welding process of embodiments of the invention.

[0071] The following section, with reference to the accompanying drawings, describes exemplary embodiments of a welding process. The welding process is used to weld conductor ends 24 of a component 26 for an electrical machine, grouped in a conductor end group 64, in order to join at least a first conductor end 24.1 of the conductor end group 64 and a second conductor end 24.2 of the conductor end group 64 together in a joining area 66. In the joining area 66, the first conductor end 24.1 and the second conductor end 24.2 lie adjacent to each other. The joining area 66 is, in particular, the area traversed by the welding jet 68 to form a weld pool 70. In some embodiments, the component is a stator 8.1, in particular a hairpin stator. The conductor ends 24.1, 24.2 are to be joined together, for example, to form a coil winding or to connect the component.The ladder group 64 can be a pair of ladders or can include more than two ladders 24.

[0072] To improve the quality of the welded joint in terms of mechanical strength and electrical conductivity, the welding process includes the following steps: a) Directing a welding jet 68 towards the joining area 66 of the conductor end group 64 to create a weld pool 70, and b) moving the welding jet 68 out of the joining area 66 into an edge area 72 of the conductor end group 64 and terminating the emission of the welding jet 68 there.

[0073] The welding process can be carried out with many different welding devices, all of which are known in terms of their system design; only the control system needs to be adapted accordingly to perform the steps mentioned above. With computer-implemented control systems, this can be achieved through appropriate programming.

[0074] First, some embodiments for a suitably adapted welding device 22.1, 22.2 are described, before details of preferred embodiments of the welding process that can be carried out with it are explained in more detail.

[0075] The following will be based on the Fig. 1 and 2 Exemplary embodiments of a welding device 22.1, 22.2 for welding conductor ends 24 during series production of a component 26 of an electric machine are described. In some embodiments, the welding device 22.1, 22.2 is part of a manufacturing plant for a stator, as otherwise known in detail from the reference [1], to which reference is made for further details.

[0076] The conductor ends 24 are arranged on the component 26 in a conductor end assembly 42. The welding device 22.1, 22.2 has a position detection device 60 for detecting, for example by sensing and / or determining, the position of predetermined conductor ends 24 of the conductor end assembly 42 to be welded. The position detection device 60 has a non-contact detection device 30.1, 30.2 for detecting the position and a computer-implemented evaluation device 58. Furthermore, the welding device 22.1, 22.2 has a welding device 61 which is configured to direct a welding jet 68 onto the conductor ends 24 to be welded depending on the position detected by the position detection device 60. The welding device 22.1, 22.2 also has a determination device 62 for determining a location 74.1-74.7 of a process end 74 depending on the position and arrangement of the conductor ends 24, 24.1, 24.2 detected by the position detection device 60. In some embodiments, the evaluation device 58, the position detection device 60 and the determination device 62 are implemented as parts of the control 52, in particular by means of a corresponding program.

[0077] The following describes exemplary embodiments of the welding device 22.1, 22.2, in which the non-contact detection device 30.1, 30.2 is a camera-based optical detection device and in which the welding device 61 is a laser device 32.1, 32.2 that directs a laser beam 5.1, 5.2 as a welding beam 68 onto the conductor ends 24 to be welded. In other embodiments, not shown here, the welding device 61 is designed as an electron beam welding device, wherein the non-contact detection device operates by means of electron beam scanning, see [6].

[0078] In the Fig. 1 and 2 Two embodiments of a welding arrangement 20.1, 20.2 are shown.

[0079] The welding arrangement 20.1, 20.2 each comprises the welding device 22.1, 22.2 for welding conductor ends 24 protruding from a component 26, as well as the component 26 to be processed.

[0080] In a preferred embodiment, component 26 is a stator 8.1 of an electric motor to be used as a traction motor for motor vehicles. The stator 8.1 is manufactured according to a manufacturing process as described and illustrated in detail in reference [1]. The welding devices 22.1, 22.2 described here serve to carry out the welding process described in that reference for joining conductor ends 24 that protrude from the stator 8.1 in order to form coil windings of the stator. The conductor ends 24 are, in particular, the free ends of hairpins 17, which have been inserted into slots of a housing / laminate stack of the stator 8.1. Accordingly, the conductor ends 24 are also referred to as pins, and a pair of conductor ends 24 to be welded together is also referred to as a pin pair.

[0081] The welding device 22.1, 22.2 has a lighting device 28.1, 28.2, an optical detection device 30.1, 30.2, a laser device 32.1, 32.2 and a holder 34.1, 34.2.

[0082] The lighting device 28.1, 28.2 serves to illuminate conductor ends 24. It can, for example, have a ring light 3.1 with a light cone 4.1 or a surface light 3.2 with a light cone 4.2.

[0083] In the illustrated embodiments, the non-contact detection device 30.1, 30.2 is designed as an optical detection device to detect conductor ends 24 illuminated by the illumination device 28.1, 28.2 in a conductor end arrangement 42 and to record their position and arrangement in a coordinate system. In some embodiments, image evaluation of a camera image – camera 44 – is provided for this purpose. Some embodiments use OCT for position detection. As explained above, in other embodiments of the non-contact detection device 30.1, 30.2, scanning by means of an electron beam can also be performed for position detection.

[0084] In the illustrated embodiments, the laser device 32.1, 32.2 is configured to direct a laser beam 5.1, 5.2 towards the conductor ends 24 depending on the detected position, in order to weld the conductor ends 24 together. In some embodiments, laser light from a laser (not shown) is guided through a fiber optic cable 1 to a laser optic 2. The laser device 32.1, 32.2 includes a scanning device 36.1, 36.2 for directing the laser beam 5.1, 5.2.

[0085] The holder 34.1, 34.2 serves to hold the component 26 and the conductor ends 24 during the welding process. For this purpose, the holder 34.1, 34.2 has a clamping device 7.2 as a welding template, as is known, for example, from reference [2]. The holder 34.1 can be movable relative to the welding device 61, for example, by rotation about an axis 40 in a direction of rotation 11, in order to position the welding beam 68 – i.e., laser beam 5.1, 5.2 – and the conductor ends 24 relative to each other, or it can be stationary, in which case the relative positioning is achieved solely by movement of the welding beam – e.g., by directing the laser beam 5.2.

[0086] Furthermore, the welding device 2.1, 22.2 can have a flow generation device 46 for generating an air curtain 6.1, 6.2, for example with an air nozzle 12, in order to remove soot 13.

[0087] The evaluation unit 58 can be part of a computer-implemented control system 52 of the device 22.1, 22.2, which includes a processor and a memory in which at least one computer program for control and evaluation is stored. In particular, the computer program includes instructions that cause the welding device 22.1, 22.2 to perform the welding process, of which preferred embodiments are described below with reference to the Fig. 3a bis 9 This will be explained in more detail. In some embodiments, the evaluation device 58 is configured to perform an image analysis of an image of the entire conductor arrangement 42 or a part thereof, in order to detect, for example by edge detection, the positions of the individual conductor ends 24 to be welded, in particular individual pin pairs, and their arrangement.

[0088] The welding process can be carried out with different welding geometries, some examples of which are shown in the Fig. 3a bis 6e are shown. Figuren 3a bis 6e Figures 74.1, 74.2, and 74.3 show examples of welding geometries with targeted positioning of the emission end. In more detail, these figures each show a top view of the conductor end group 64, which here is configured as a conductor end pair. Figures 64, labeled a, show the end faces before the welding process; figures 74.b show the end faces during welding using existing solutions not covered by the invention; and figures 74.c, 74.d, and 74.e show the end faces at the end of the welding process for different embodiments of the welding process according to the invention. The black dot shown in figures 74.b to 74.e. schematically indicates the end of the process 74, i.e., the end of the welding process where the emission of the welding jet 68 ceases.

[0089] The Figuren 3a bis 3e The figures illustrate the application of the welding process to a welding geometry shaped like an ellipse 76. In other words, the welding jet 68 is scanned across an elliptical impact zone in the joining area 66, so that the elliptically shaped joining area is covered by the welding jet. In the previous approach according to Fig. 3b The emission of the welding jet 68 in the joining area 66 was terminated. This could lead to the formation of pores (keyholes) in the joining area, with a corresponding impairment of the weld quality. In contrast, in the embodiments according to Fig. 3c bis 3e The welding jet 68 is guided selectively from the joining area 66 into an edge area 72. There, the emission of the welding jet is terminated. Thus, the process end 74 is selectively positioned outside the joining area 66, particularly at or near the edge. As the Fig. 3c bis 3e As shown, the emission end can be located at different locations 74.1, 74.2, 74.3 at the edge or near the edge of the conductor end group 64. For example, the welding jet 68 is directed into a corner area at the end of the process 74 - Fig. 3c und 3e , at 74.1 or 74.3 - or at an edge area of ​​a conductor end 24, 24.1, 24.2 - Fig. 3d , at 74.2 - procedure.

[0090] As the Figuren 4a bis 4e As shown, the targeted positioning 74.1, 74.2, 74.3 of the process end 74 in the edge region 72 can also be transferred to a welding geometry formed as a rectangle 78, where the welding jet 68 is guided within a rectangle to generate the corresponding weld pool 70. In other words, the welding jet 68 is scanned in the joining area 66 over a rectangular impact zone, so that the joining area, which is then rectangular, is traversed by the welding jet.

[0091] The Figuren 5a bis 5e show in a corresponding manner how Fig. 3a bis 3e for the elliptical and Fig. 4a bis 4e For the rectangular welding geometry, the welding process is applied to a split geometry 80, where the welding jet 68 is directed in different sub-areas on the first conductor end 24.1, on the second conductor end 24.2, and in the joining area 66 to create a weld pool 70. In other words, the welding jet 68 covers a multi-zone joining area 66 with different zones 66.1, 66.2, 66.3. Here too, at the end of the welding process, the welding jet 68 is guided into the edge area 72; again, the process end 74 can be positioned at or near the edge at the different locations 74.1, 74.2, 74.3 mentioned above.

[0092] In the Fig. 6a bis 6e It is shown how the process end 74 can also be positioned specifically at or near the edge in a gap weld with a line 81 as the weld geometry. In other words, a linear joining area 66 is traversed with the welding jet 68. Here too, at the end of the process, the welding jet 68 is directed out of the joining area 66 to one of the exemplary in Fig. 6c bis 6d The locations shown, 74.1 to 74.3, are located at or near the edge of the ladder end group 64, where the emission is terminated.

[0093] While in the Fig. 3c bis 3e, 4c bis 4e , 5c bis 5e und 6c bis 6e Different examples of the positioning 74.1-74.3 of the process end 74 in a top view of the end faces 86 of the ladder ends 24.1, 24.2 (e.g. in coordinates of positioning in an xy-plane parallel to the end faces 86) are shown in the Figuren 7 bis 11 Side views of the ladder end group 64 are shown, illustrating different variations of targeted positioning of the process end in the vertical direction (e.g., z-direction). In particular, the Figuren 7 bis 9 the conductor end group 64 with the conductor ends 24 to be welded, an example of the melt pool 70 created during welding, the laser optics 2 with the laser beam 5.1, 5.2 and various examples of the targeted positioning 74.5-74.7 of the emission end, in particular with regard to the z-direction (direction in the longitudinal extension of the conductor ends).

[0094] Viewed from above, the emission end can be seen as in the Fig. 3c bis 3e, 4c bis 4e , 5c bis 5e und 6c bis 6e shown, located at any point on or near the edge of the ladder end group.

[0095] As in Fig. 7 As shown, the process end 74, 74.5 can be located near the wire edge of one of the joining partners (first conductor end 24.1 or second conductor end 24.2) in the edge region of the weld pool 70. For example, the welding jet is moved to a location 74.4 on the end face 86 of one of the conductor ends 24, 24.1, 24.2 near its edge 88 at the process end 74.

[0096] Fig. 8 This shows the example of positioning 74.6 of the process end 74 on edge 88.

[0097] Fig. 9 bis 11 Examples of positioning 74.7, 74.6, 74.7 of the process end outside the melt pool 70 are shown. Fig. 9 The process end 74 is positioned on a side surface 90 of one of the joining partners. Fig. 10 The process end 74 is positioned outside the conductor ends 24.1, 24.2, e.g., on the clamping device 7.2, such as a clamping template. For this purpose, the welding jet 68 is moved so that it hits the clamping device 7.2 outside the conductor end group 64, where the emission is terminated.

[0098] In the example of the Fig. 11 For this purpose, a protective cover 82 is provided for the clamping device 7.2, such as in particular a separately provided sacrificial plate 84, the position of which is also shown in Fig. 2 as indicated.

[0099] The emission can be stopped in different ways. For example, the welding beam 68 is switched off at the end of the process. Alternatively or additionally, an aperture (not shown) can be inserted into the welding beam.

[0100] After a ladder end group 64 of the ladder end arrangement 42 has been welded in this way, the process is repeated for each further ladder end group 64 of the ladder end arrangement 42 in which ladder ends are to be welded.

[0101] For this purpose, the position of each conductor end 24, 24.1, 24.2 and their arrangement are recognized in order to carry out the welding and also the targeted positioning of the process end according to the recognized conductor end position and arrangement. Bezugszeichenliste:

[0102] 1 Fiber optic cable 2 Laser optics (scanner) 3.1 Ring light 3.2 Area light 4.1 Ring light cone 4.2 Area light cone 5.1 Laser beam 5.2 Laser beam 6.1 Air curtain 6.2 Air curtain 7.2 Tensioning device 8.1 Stator 11 Rotation direction 12 Air nozzle 13 Flue gas / soot 17 Hairpins 20.1 Welding arrangement 20.2 Welding arrangement 22.1 Welding device 22.2 Welding device 24 Conductor ends 24.1 First conductor end 24.2 Second conductor end 26 Component 28.1 Lighting device 28.2 Lighting device 30.1 Optical detection device 30.2 Optical detection device 32.1 Laser device 32.2 Laser device 34.1 Mounting bracket 34.2 Mounting bracket 36.1 Scanning device 36.2 Scanning device 40 Central axis 42 Conductor end arrangement 44 Camera 46 Flow generation device 52 Control 58 Evaluation device 60 Position detection device 61 Welding device 62 Determination device 64 Conductor end group 66 Joining area 66.1 First zone of the joining area 66.2 Second zone of the joining area 66.3 Third zone of the joining area 68 Welding jet 70 Melt pool 72 Edge area 74 Process end 74.1 Location of targeted positioning of the process end (first example) 74.2 Location of targeted positioning of the process end (second example) 74.3 Location of targeted positioning of the process end (third example) 74.4 Location of targeted positioning of the process end (fourth example) 74.5 Location of targeted positioning of the process end (fifth example) 74.6 Location of targeted positioning of the process end (sixth example) 74.7 Location of targeted positioning of the process end (seventh example) 76 Ellipse 78 Rectangle 80 Split geometry 81 Line 82 Protective cover 84 Sacrificial plate 86 End surface 88 Edge 90 Side surface.

Claims

1. Welding method for welding conductor ends (24, 24.1, 24.2) of a component (26) for an electrical machine grouped in a conductor end group (64), wherein at least a first conductor end (24, 24.1) of the conductor end group (64) and a second conductor end (24, 24.2) of the conductor end group (64) are to be joined together in a joining area (66) of the conductor end group (64) where the first conductor end (24.1) and the second conductor end (24.2) are adjacent, comprising: a) directing a welding jet (68) onto the joining area (66) of the conductor end group (64) to produce a weld pool (70), and b) moving the welding jet (68) out of the joining area (66) into an edge area (72) of the conductor end group (64) and terminating the emission of the welding jet (64) there.

2. Welding process according to claim 1, characterized by the step: Positioning of the ladder ends to be welded (24, 24.2, 24.2) of the ladder end group throughClamping using a clamping template (7.2).

3. Welding process according to claim 1 or 2, characterized by the fact that as a welding beam (68) a laser beam (5.1, 5.2) is directed at the conductor end group (64).

4. Welding process according to one of the preceding claims, characterized by that Step a) comprises: scanning the joining area (66) using the welding jet (68), wherein the joining area (66) is elliptical, polygonal, in particular rectangular, multi-zone or linear.

5. Welding process according to one of the preceding claims, characterized by thatStep b) comprises at least one or more of the following steps: b1.1) passing the welding jet (68) into a corner region of the ladder end group (64); b1.2) passing the welding jet (68) into an edge region of the weld pool (70); b1.3) passing the welding jet (68) into an edge region of a ladder end (24, 24.1, 24.2) of the ladder end group (64); b1.4) passing the welding jet (68) into an edge region of an end face (86) of a ladder end (24, 24.1, 24.2) of the ladder end group; b1.5) passing the welding jet (68) onto an edge (88) of a ladder end (24, 24.1, 24.2); b1.6) Method of the welding jet (68) such that it strikes a side surface (90) of the ladder end group (64), in particular a ladder end (24, 24.1, 24.2) thereof; b1.7) Method of the welding jet (68) such that it strikes a clamping template outside the ladder end group (64); b1.8) Method of the welding jet (68) such that it strikes a protective cover (82), in particular a sacrificial plate (84), provided for this purpose outside the conductor end group (64).

6. Welding process according to one of the preceding claims, characterized by that Step b) includes at least one or more of the following steps: b2.1) Moving an aperture into the welding jet; b2.2) Switching off the welding jet.

7. Welding process according to one of the preceding claims, characterized by Repeat steps a) and b) to weld conductor ends (24, 24.1, 24.2) of another conductor end group (64) of component (26).

8. Welding process according to one of the preceding claims, characterized by the step to be carried out before step a): 0) Identifying the position and / or arrangement of the ladder ends (24, 24.1, 24.2) to be welded of the ladder end group (64), as well as throughthe step: 1) Determining the location (74.1-74.5) of the termination of the emission of the welding jet (68) depending on the position and / or arrangement detected in step 0).

9. Method for manufacturing a coil winding of a hairpin stator, characterized by Forming the coil winding from a plurality of hairpin-shaped conductor sections, wherein conductor ends (24, 24.1, 24.2) of the conductor sections are joined by means of a welding process according to one of the preceding claims.

10. Welding device (22.1, 22.2) for welding conductor ends (24, 24.1, 24.2) of a component (26) for an electrical machine grouped in a conductor end group (64), wherein at least a first conductor end (24, 24.1) of the conductor end group (64) and a second conductor end (24, 24.2) of the conductor end group (64) are to be joined together in a joining area (66) of the conductor end group (64), where the first conductor end (24, 24.1) and the second conductor end (24, 24.2) are located next to each other, wherein the welding device (22.1, 22.2) comprises: a welding device (61) with which a welding jet (68) can be directed onto the conductor end group (64), and a control system which is configured to direct the welding device (61) to direct the welding jet (68) onto the joining area (66) of the conductor end group (64) in order to create a weld pool (70), and to move the welding jet (68) out of the joining area (66) into an edge area (72) of the conductor end group (64) and to terminate the emission of the welding jet (68) there.

11. Welding device (22.1, 22.2) according to claim 10, characterized byat least one or more of the following units: 11.1 a holder (34.1, 34.2) for the component (26) from which the conductor ends (24, 24.2, 24.2) to be joined protrude in a conductor end arrangement (42); 11.2 a welding template for positioning the conductor ends (24, 24.2, 24.2); 11.3 a position detection device (60) configured to detect the position and / or arrangement of the conductor ends (24, 24.1, 24.2) to be welded in the conductor end group (64); 11.4 a determination device (62) for determining the location (74.1-74.7) of the termination of the emission of the welding jet (68), in particular depending on the through the position detection device (60) is set up to detect the position and / or arrangement.

12. Welding device (22.1, 22.2) according to one of claims 10 or 11, characterized by thatthe welding device (61) is selected from the group comprising a laser device (32.1, 32.2) for directing a laser welding beam (5.1, 5.2) onto the conductor ends (24, 24.1, 24.2) to be welded and an electron beam welding device for directing an electron beam onto the conductor ends (24, 24.1, 24.2) to be welded.

13. Welding device (22.1, 22.2) according to one of claims 10 to 12, characterized by that the control (52) is configured to cause the welding device (61) to carry out the welding process according to one of claims 1 to 8.

14. Manufacturing plant for manufacturing a hairpin stator, comprising a welding device (22.1, 22.2) according to any one of claims 10 to 13.

15. Computer program comprising instructions that cause a welding device (22.1, 22.2) according to any one of claims 10 to 13 to perform the method according to any one of claims 1 to 8.

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